TROBaseSuperChannel
Overview
This is the base abstract class for all super channels on the Delphi platform. Direct descendants of this class are TROBaseSuperTCPChannel and TROBaseSuperHTTPChannel. This class implements all common superchannel interfaces and implements or declares all common members.
Note: there are many class members missing descriptions because they are related to internal superchannel mechanics that users are unlikely to deal with.
Location
- Unit: uROBaseSuperChannel.pas
- Ancestry: TComponent | TROComponent | TROBaseConnection | TROTransportChannel | TROBaseActiveEventChannel | TROBaseSuperChannel
constructor Create override
Standard component constructor
constructor Create(aOwner: TComponent)
Parameters:
- aOwner: Owner
Active
Allows to get channel's activity state, whether the channel active i.e. attempts to connect or already connected. Allows to activate and deactivate the channel.
property Active: Boolean read write
Assign override (declared in TROTransportChannel)
Copies the contents of another, similar object.
procedure Assign(Source: TPersistent)
Parameters:
- Source: Instance whose properties will be copied
AssignEvents protected override
Copies the events of another, similar object.
procedure AssignEvents(aSource: TROTransportChannel)
Parameters:
- aSource: Instance whose properties will be copied
AssignSpecificProperties protected override
Copies the specific properties of another, similar object.
procedure AssignSpecificProperties(aSource: TROTransportChannel)
Parameters:
- aSource: Instance whose properties will be copied
AsyncException protected virtual (declared in TROTransportChannel)
Notifies about an exception in an asynchronous mode.
procedure AsyncException(aAsyncInterface: IROAsyncInterface; AsyncException: Exception)
Parameters:
- aAsyncInterface: Exception source
- AsyncException: Exception data
AutoReconnect protected
Specifies whether to use auto reconnect feature if the specified server is not available.
property AutoReconnect: Boolean read write
AutoReconnectBehavior protected
Controls the auto-reconnect behavior, if enabled. For possible auto-reconnect modes see TROSCAutoReconnectBehavior enum.
property AutoReconnectBehavior: TROSCAutoReconnectBehavior read write
BeforeDispatch protected override
Allows an implimentation to do necessary preparatory actions (checking the readiness of the channel, restore session data, etc.).
procedure BeforeDispatch(aMessage: IROMessage)
Parameters:
- aMessage: Message
Busy (declared in TROTransportChannel)
Informs whether the channel is currently busy executing a remote request (true) or not (false). Most channels (except most notably the TROSuperTCPChannel) are only capable of performing one request at a time; if a second request is attempted while the channel is Busy, an EROChannelBusy exception will be raised.
property Busy: Boolean read
CallbackEvents protected (declared in TROBaseActiveEventChannel)
Sends event to each registered IROEventReceiver
procedure CallbackEvents(aData: TStream; aThread: TThread)
Parameters:
- aData: Data stream
- aThread: Working thread to process the event
ChangeServerLocator protected override
procedure ChangeServerLocator(var aFaultStartLocatorIdx: Integer; var aRetry: Boolean; const aException: Exception)
Parameters:
- aFaultStartLocatorIdx:
- aRetry:
- aException:
ChannelMatchingTargetUri (declared in TROTransportChannel)
Creates a client channel instance with type, target host and target port matching the provided target Uri.
F.e. for provided uri supertcp://192.168.1.100:7020/bin this method will return an instance of the Super Tcp channel with target host set to 192.168.1.100 and port set to 7020.
class function ChannelMatchingTargetUri(const aUri: TROUri): TROTransportChannel
Parameters:
- aUri: Server Uri
ChannelMatchingTargetUrl (declared in TROTransportChannel)
class function ChannelMatchingTargetUrl(const aUrl: string): TROTransportChannel
Parameters:
- aUrl:
CheckProperties virtual (declared in TROTransportChannel)
Validates channel properties
procedure CheckProperties
CheckStatus protected
Indicates whether an answer is received after an InvokeRequest.
function CheckStatus(const aMessageID: string): Boolean
Parameters:
- aMessageID: Value of the previously called InvokeRequest result
ClientId protected
The unique identifier of the client and it's session on the server. See TROMessage description for more details. The property is assigned automatically during the process of data exchange between the client and the server.
property ClientId: TGUID read write
Connected
Returns true if the channel is connected to the server.
property Connected: Boolean read
ConnectEvent
property ConnectEvent: TROEvent read
ConnectionWaitTimeout protected
The timeout to establish connection to the server. Expressed in milliseconds, the default value is 10000 (10 sec).
property ConnectionWaitTimeout: Integer read write
ConnectTimeout
Connection timeout
property ConnectTimeout: Integer read write
CreateWorkerThread protected virtual abstract
function CreateWorkerThread: TThread
CurrentLocator (declared in TROTransportChannel)
Returns which of the fail-over/load balancing servers configured in the ServerLocators is currently active. Depending on the DispatchOptions defined, this value might change with each request, or only if the current server fails.
property CurrentLocator: TROServerLocator read write
DecryptStream (TStream, TStream) protected overload (declared in TROBaseConnection)
Decrypt stream
procedure DecryptStream(const Source: TStream; const Dest: TStream)
Parameters:
- Source: Source
- Dest: Destination
DecryptStream (TStream) protected overload (declared in TROBaseConnection)
Decrypt stream
procedure DecryptStream(const Stream: TStream)
Parameters:
- Stream: Stream
Dispatch (IROMessage) protected reintroduce overload (declared in TROTransportChannel)
Sends a request message through the Self
channel for processing and gets back an aMessage
. CodeGen uses this method when generating a proxy from RODL Files.
procedure Dispatch(aMessage: IROMessage)
Parameters:
- aMessage: (In/out) message data
DispatchOptions
Configures the available fail-over and load balancing options provided by the Remoting SDK. By default, channels are set up to talk to one specific server only. Two independent options are available to provide fail-over and load balancing:
- Enables fail-over support. If the connection to any given server fails, the channel will automatically keep trying the next server specified in ServerLocators, until a working server is found or all servers have been tried.
- Enables load-balancing support. Each request dispatched through the channel will go to a different server configured in ServerLocators, resulting in calls being more or less equally distributed over the available servers.
Enabling any of these options obviously requires the server to be implemented in a stateless way, so that it does not depend on all requests from a client going to the same server. This implies using a class factory different from Per-Client and, if sessions are used, a session manager that allows sharing of session state between servers.
property DispatchOptions: TRODispatchOptions read write
DoAfterProbingServerEvent protected override
Fires OnAfterProbingServer event
procedure DoAfterProbingServerEvent(const aServerLocator: TROServerLocator; const aFailed: Boolean)
Parameters:
- aServerLocator: Server locator
- aFailed:
DoAfterProbingServersEvent protected override
Fires OnAfterProbingServer event
procedure DoAfterProbingServersEvent(const aProbedCount: Integer; const aEnabledCount: Integer; const aDisabledCount: Integer)
Parameters:
- aProbedCount:
- aEnabledCount:
- aDisabledCount:
DoBeforeDecryptEvent protected virtual (declared in TROBaseConnection) obsolete
procedure DoBeforeDecryptEvent(aEncryptedStream: TStream)
Parameters:
- aEncryptedStream: Stream
DoBeforeProbingServerEvent protected override
Fires OnBeforeProbingServer event
procedure DoBeforeProbingServerEvent(const aServerLocator: TROServerLocator)
Parameters:
- aServerLocator: Server locator
DoBeforeProbingServersEvent protected override
Fires OnBeforeProbingServers event
procedure DoBeforeProbingServersEvent
DoNeedSSL protected virtual (declared in TROTransportChannel)
Detects SSL state
function DoNeedSSL: Boolean
DoProcessError protected
function DoProcessError(const aId: Integer; const aErrorNo: Integer): Boolean
Parameters:
- aId:
- aErrorNo:
DoReceiveStreamEvent protected override
Fires OnSendStream event
procedure DoReceiveStreamEvent(const Dest: TStream)
Parameters:
- Dest: Stream
DoReconnect protected
procedure DoReconnect(var aRestartLoop: Boolean)
Parameters:
- aRestartLoop:
DoSendStreamEvent protected override
Fires OnSendStream event
procedure DoSendStreamEvent(const Source: TStream)
Parameters:
- Source: Stream
DoServerLocatorAssignmentEvent protected override
Fires OnServerLocatorAssignment event
procedure DoServerLocatorAssignmentEvent(const aLocator: TROServerLocator; const aException: Exception)
Parameters:
- aLocator:
- aException:
Encryption (declared in TROBaseConnection) obsolete
This is DES based enscryption, it is obsolete because works only for Delphi. Use message envelope AES Encryption Envelope instead.
property Encryption: TROEncryption read write
EncryptStream (TStream, TStream) protected overload (declared in TROBaseConnection)
Encrypt stream
procedure EncryptStream(const Source: TStream; const Dest: TStream)
Parameters:
- Source: Source
- Dest: Destination
EncryptStream (TStream) protected overload (declared in TROBaseConnection)
Encrypt stream
procedure EncryptStream(const Stream: TStream)
Parameters:
- Stream: Stream
EventReceiverList protected (declared in TROBaseActiveEventChannel)
Provides a list of registered IROEventReceiver
property EventReceiverList: TInterfaceList read
EventThreadPool
Refers to the TROThreadPool instance to provide a thread pool to execute event handling routines on. If the thread pool is not set explicitly it is created autromatically upon access.
property EventThreadPool: TROThreadPool read write
FaultToleranceLocatorIdx (declared in TROTransportChannel)
property FaultToleranceLocatorIdx: Integer read write
FindWaitingRequest protected
function FindWaitingRequest(aList: TList<TROWaitingRequest>; aId: Integer): TROWaitingRequest
Parameters:
- aList:
- aId:
GetBusy protected virtual (declared in TROTransportChannel)
Returns current channel state
function GetBusy: Boolean
GetChannelFromPool protected virtual (declared in TROTransportChannel)
function GetChannelFromPool: TROTransportChannel
GetStrippedTargetUrl protected virtual
function GetStrippedTargetUrl: string
GetTransportObject protected virtual (declared in TROTransportChannel)
Returns itself.
function GetTransportObject: TObject
HasData protected
This method is called when incoming data is present.
procedure HasData(aId: Integer; aData: TStream)
Parameters:
- aId:
- aData:
InDestroyingState protected
Returns current state
function InDestroyingState: Boolean
InitialConnect protected
function InitialConnect: Boolean
InitServerLocator protected override
Sets CurrentLocator
function InitServerLocator: Integer
InitWorkerThread protected
procedure InitWorkerThread
InvokeRequest protected
Indicates whether an answer is received after an InvokeRequest.
function InvokeRequest(aRequest: TStream; aGetResponse: Boolean): string
Parameters:
- aRequest: Id of a waiting response
- aGetResponse: Response data
IsEncryptionUsed protected (declared in TROBaseConnection)
Checks if encryption was used
function IsEncryptionUsed: Boolean
IsProbeMode protected (declared in TROTransportChannel)
property IsProbeMode: Boolean read
IsStreamEncrypted protected (declared in TROBaseConnection)
Checks state of stream
function IsStreamEncrypted(Source: TStream): Boolean
Parameters:
- Source: Stream
LaunchAsyncTask protected (declared in TROTransportChannel)
procedure LaunchAsyncTask(aRequest: IROAsyncRequest)
Parameters:
- aRequest:
LoadBalancerLocatorIdx (declared in TROTransportChannel)
property LoadBalancerLocatorIdx: Integer read write
LoadSSL protected virtual (declared in TROTransportChannel)
Loads SSL library if SSL protocol is used
procedure LoadSSL
MaxPackageSize
Sets the maximum size for data packages that the channel will transport (default is 10485760, 10 MB).
property MaxPackageSize: Integer read write
Notification protected override
Forwards notification messages to all owned components.
procedure Notification(AComponent: TComponent; Operation: TOperation)
Parameters:
- AComponent: component
- Operation: operation
OnAfterEncrypt (declared in TROBaseConnection)
Fired after stream was encrypted
property OnAfterEncrypt: TROBaseConnectionOperation read write
delegate: procedure OnAfterEncrypt(Sender: TROBaseConnection; aEncryptedStream: TStream)
OnAfterProbingServer
Fires after the channel is done probing a specific server for availability. You can use this event to check the result of the probing, possibly to update internal data structures or to display server status in the user interface.
property OnAfterProbingServer: TROEndProbeServerEvent read write
OnAfterProbingServers
Fires after the channel is done probing all servers for availability. You can use this event to check the result of the probing, possibly to update internal data structures or to display server status in the user interface.
property OnAfterProbingServers: TROEndProbeServersEvent read write
OnAsyncException (declared in TROTransportChannel)
Fires when exception is raised in asynchronous mode
property OnAsyncException: TROAsyncExceptionEvent read write
delegate: procedure OnAsyncException(Sender: TROTransportChannel; Async: IROAsyncInterface; anException: Exception)
OnBeforeDecrypt (declared in TROBaseConnection)
Fired before stream will be decrypted
property OnBeforeDecrypt: TROBaseConnectionOperation read write
delegate: procedure OnBeforeDecrypt(Sender: TROBaseConnection; aEncryptedStream: TStream)
OnBeforeProbingServer
Fires before the channel starts probing a specific server for availability. You can use this event to:
- check or adjust the server configuration
- to include/exclude the server from being probed by changing the TROServerLocator property.
property OnBeforeProbingServer: TROBeginProbeServerEvent read write
OnBeforeProbingServers
Fires before the channel starts probing all servers for availability. You can use this event:
- to check or adjust the server configurations
- to include/exclude individual server from being probed by changing their TROServerLocator properties.
property OnBeforeProbingServers: TROBeginProbeServersEvent read write
OnConnected
Fires when channel is connected to server
property OnConnected: TNotifyEvent read write
OnDisconnected
Fires when the active connection to the server has been dropped or lost.
property OnDisconnected: TNotifyEvent read write
OnException (declared in TROTransportChannel)
Fires if an exception is raised during the execution of a remote request.
This could be an exception returned from the server, a communication problem or an error within the client.
Depending on the type of error, your event handler can try to rectify the problem, and set aRetry to true to have the channel try and perform the request again. For example, an application could show a dialog asking the user to confirm if his internet connection is available, with Cancel and Retry buttons.
If aRetry is set to true and the call succeeds at the second attempt, the call will return to the original code that initiated the request, as if the exception never happened.
property OnException: TROExceptionEvent read write
delegate: procedure OnException(Sender: TROTransportChannel; anException: Exception; var aRetry: Boolean)
OnLoginNeeded
Fires if an EROSessionNotFound (or the descendant SessionNotFoundException) exception is raised during the execution of a remote request. This usually indicates that the server cannot authenticate the client or that the session has expired. The most common use for this event is to perform a call to a special Login service provided by the server (possibly after prompting the user to enter username and password), and to set the aRetry parameter to true if login was successful.
property OnLoginNeeded: TROExceptionEvent read write
OnProgress
This event fires as the channel is transferring data for a request or response to or from the server, informing of the current progress. It can be used to keep the user interface updated during lengthy transfers,e.g. by showing a progress bar or the remaining transfer volume. Note: the accuracy and frequency of calls to OnProgress depends on the channel type; since channels transport data packets in different sized chunks (or even all-at-once), OnProgress might show a very fine progress for some channels, while jumping from 0 to 100% in one step with others.
property OnProgress: TProgressEvent read write
OnReceiveStream
Fires after a stream with a response message has been received from the server. Use this event handler to inspect and possibly modify the stream, before it continues to be processed by the higher levels of the Remoting SDK framework.
property OnReceiveStream: TStreamDispatch read write
OnSendStream
Fires just as a stream with a request message will be sent to the server. The event handler can inspect and possibly modify the stream, before it continues to be sent off to the server.
property OnSendStream: TStreamDispatch read write
OnServerLocatorAssignment
Fires before changing of a server locator.
property OnServerLocatorAssignment: TServerLocatorAssignment read write
Probe protected (declared in TROTransportChannel)
Checks the accessibility of servers from the ServerLocators. This method is intended to provide fail-over and load balancing support in the Remoting SDK Architecture.
function Probe(aServerLocator: TROServerLocator): Boolean
Parameters:
- aServerLocator: Server locator
ProbeAll protected (declared in TROTransportChannel)
Checks the availability of all known servers.
procedure ProbeAll
ProbeFrequency
Sets at what intervals, in milliseconds, the channel will probe the servers configured in ServerLocators for availability. The default value is 60,000 (60 seconds). See the ProbeServers property for a more detailed description. Although somewhat misnamed, this property defines the Interval between probes, not the actual probing Frequency. The property name is persisted for backward compatibility.
property ProbeFrequency: Cardinal read write
ProbeServers
Toggles whether the channel will continuously probe the servers configured in ServerLocators for availability. If enabled (true), the channel will ping all servers at a regular interval to determine if they are reachable. If a server fails to respond, it will be disabled for future calls until a later probe can reach it again. The interval between probes can be configured using the ProbeFrequency property. By default, server probing is turned off.
property ProbeServers: Boolean read write
ProcessEvent protected
procedure ProcessEvent(aData: TStream)
Parameters:
- aData:
ReconnectDelay protected
The time interval to pass between reconnect attempts, in millisecnds. The default is 500 (0.5 second).
property ReconnectDelay: Integer read write
ReconnectEvent
property ReconnectEvent: TROEvent read
RegisterEventReceiver protected virtual (declared in TROBaseActiveEventChannel)
Registers a new event receiver object aReceiver in the specified channel. This procedure is needed to further use the aReceiver as receiver for callback events.
procedure RegisterEventReceiver(aReceiver: IROEventReceiver)
Parameters:
- aReceiver: the event receiver that should be registered.
RequestTimeout
The timeout to complete the remote request on the server. Expressed in milliseconds, the default value is 60000 (60 sec). All requests that last longer than the timeout specified are considered failed.
property RequestTimeout: Integer read write
ResetProbingClone protected override
Resets channel that is used for probing
procedure ResetProbingClone(aProbe: TROTransportChannel)
Parameters:
- aProbe: Probing clone
RetrieveMetadata protected virtual (declared in TROTransportChannel)
Returns server-side RODL.
procedure RetrieveMetadata(out Dest: TStream)
Parameters:
- Dest: Stream
RetrieveResponse protected
Indicates whether an answer is received after an InvokeRequest.
procedure RetrieveResponse(const aMessageID: string; aResponse: TStream)
Parameters:
- aMessageID: Id of a waiting response
- aResponse: Response data
RetrieveRODL protected (declared in TROTransportChannel)
This method is used for to obtaining the RODL library from the server without havin to rely on a channel-specific mechanism (such as a HTTP request to http://servername:port/rodl).
procedure RetrieveRODL(out RODLLibrary: TRODLLibrary)
Parameters:
- RODLLibrary: Result
ReturnChannelToPool protected virtual (declared in TROTransportChannel)
procedure ReturnChannelToPool(aChannel: TROTransportChannel)
Parameters:
- aChannel:
ROActiveAsyncTransportChannel_InvokeRequest (TStream, Boolean, TROEvent): string protected overload virtual abstract
function ROActiveAsyncTransportChannel_InvokeRequest(aRequest: TStream; aGetResponse: Boolean; aEvent: TROEvent): string
Parameters:
- aRequest:
- aGetResponse:
- aEvent:
ROFreeNotification (declared in TROComponent)
Forwards notification messages to all owned components.
procedure ROFreeNotification(aComponent: TComponent)
Parameters:
- aComponent: component
RORemoveFreeNotification (declared in TROComponent)
Forwards notification messages to all owned components.
procedure RORemoveFreeNotification(aComponent: TComponent)
Parameters:
- aComponent: component
SendRemoveNotification protected (declared in TROComponent)
Forwards notification messages to all owned components.
procedure SendRemoveNotification(aComponent: TComponent)
Parameters:
- aComponent: component
ServerLocators
Optionally, this collection property can be filled to contain a list of possible servers to be used for fail-over or load balancing purposes. Depending on the settings configured in DispatchOptions, the channel will automatically spread calls over the available servers, or fall back to another server if one fails.
property ServerLocators: TROServerLocatorCollection read write
SessionId protected
The unique identifier of the current session on the server. The same as ClientId.
property SessionId: TGUID read write
SetAsyncBusy protected override
procedure SetAsyncBusy(const Value: Boolean)
Parameters:
- Value:
SetConnectedState protected
procedure SetConnectedState
SetInactive protected virtual
procedure SetInactive
SetServerLocator protected (declared in TROTransportChannel)
Retrieves the location details of a server from aServerLocator
.
procedure SetServerLocator(aServerLocator: TROServerLocator; anException: Exception)
Parameters:
- aServerLocator: Configuration data of the server
- anException: Exception
StoreActive
Controls whether the Active property value is stored in the dfm file.
property StoreActive: Boolean read write
SuperChannel_RaiseError protected virtual abstract
procedure SuperChannel_RaiseError(aCode: Integer)
Parameters:
- aCode:
SynchronizedProbing
Determines whether server probing happens in the context of the main VCL thread (true, default) or in a background worker thread. See the ProbeServers property for a more detailed description.
property SynchronizedProbing: Boolean read write
SynchronizeEvents
According to the superchannel nature every remote request is processed using it's own background thread. This property controls on which thread to execute the event handlers for events connected with each remote request. If the property is set to true than all event handlers are executed on the main application thread, otherwise they are executed on the request's background thread.
WARNING: This property has no effect on OnSendStream and OnReceiveStream events, they are always executed in main thread.
property SynchronizeEvents: Boolean read write
TargetUri (declared in TROTransportChannel)
Target URI
property TargetUri: TROUri read write
TargetUrl
The address of the server.
property TargetUrl: string read write
TerminateWorkerThread protected
procedure TerminateWorkerThread
ThreadSafe protected (declared in TROTransportChannel)
property ThreadSafe: Boolean read write
TriggerProgress protected override
Fires OnProgress event
procedure TriggerProgress(aType: TProgressType; aDirection: TProgressDirection; aTransfered: Integer; aTotal: Integer)
Parameters:
- aType: progress type
- aDirection: direction
- aTransfered: transfered bytes
- aTotal: total bytes
UnregisterEventReceiver protected virtual (declared in TROBaseActiveEventChannel)
Unregisters the specified IROEventReceiver aReceiver in the specified channel.
procedure UnregisterEventReceiver(aReceiver: IROEventReceiver)
Parameters:
- aReceiver: The event receiver that should be unregistered.
UnregisterEventReceivers protected (declared in TROBaseActiveEventChannel)
Unregisters the all event receivers in the specified channel.
procedure UnregisterEventReceivers
WaitForActive
procedure WaitForActive(const aTimeout: Integer)
Parameters:
- aTimeout:
WaitingRequests protected
Internal storage of remote requests awaiting for response.
property WaitingRequests: TThreadList<TROWaitingRequest> read
WorkerThread protected
Internal background threads management property.
property WorkerThread: TThread read
Active
Allows to get channel's activity state, whether the channel active i.e. attempts to connect or already connected. Allows to activate and deactivate the channel.
property Active: Boolean read write
AutoReconnect protected
Specifies whether to use auto reconnect feature if the specified server is not available.
property AutoReconnect: Boolean read write
AutoReconnectBehavior protected
Controls the auto-reconnect behavior, if enabled. For possible auto-reconnect modes see TROSCAutoReconnectBehavior enum.
property AutoReconnectBehavior: TROSCAutoReconnectBehavior read write
Busy (declared in TROTransportChannel)
Informs whether the channel is currently busy executing a remote request (true) or not (false). Most channels (except most notably the TROSuperTCPChannel) are only capable of performing one request at a time; if a second request is attempted while the channel is Busy, an EROChannelBusy exception will be raised.
property Busy: Boolean read
ClientId protected
The unique identifier of the client and it's session on the server. See TROMessage description for more details. The property is assigned automatically during the process of data exchange between the client and the server.
property ClientId: TGUID read write
Connected
Returns true if the channel is connected to the server.
property Connected: Boolean read
ConnectionWaitTimeout protected
The timeout to establish connection to the server. Expressed in milliseconds, the default value is 10000 (10 sec).
property ConnectionWaitTimeout: Integer read write
ConnectTimeout
Connection timeout
property ConnectTimeout: Integer read write
CurrentLocator (declared in TROTransportChannel)
Returns which of the fail-over/load balancing servers configured in the ServerLocators is currently active. Depending on the DispatchOptions defined, this value might change with each request, or only if the current server fails.
property CurrentLocator: TROServerLocator read write
DispatchOptions
Configures the available fail-over and load balancing options provided by the Remoting SDK. By default, channels are set up to talk to one specific server only. Two independent options are available to provide fail-over and load balancing:
- Enables fail-over support. If the connection to any given server fails, the channel will automatically keep trying the next server specified in ServerLocators, until a working server is found or all servers have been tried.
- Enables load-balancing support. Each request dispatched through the channel will go to a different server configured in ServerLocators, resulting in calls being more or less equally distributed over the available servers.
Enabling any of these options obviously requires the server to be implemented in a stateless way, so that it does not depend on all requests from a client going to the same server. This implies using a class factory different from Per-Client and, if sessions are used, a session manager that allows sharing of session state between servers.
property DispatchOptions: TRODispatchOptions read write
Encryption (declared in TROBaseConnection) obsolete
This is DES based enscryption, it is obsolete because works only for Delphi. Use message envelope AES Encryption Envelope instead.
property Encryption: TROEncryption read write
EventReceiverList protected (declared in TROBaseActiveEventChannel)
Provides a list of registered IROEventReceiver
property EventReceiverList: TInterfaceList read
EventThreadPool
Refers to the TROThreadPool instance to provide a thread pool to execute event handling routines on. If the thread pool is not set explicitly it is created autromatically upon access.
property EventThreadPool: TROThreadPool read write
FaultToleranceLocatorIdx (declared in TROTransportChannel)
property FaultToleranceLocatorIdx: Integer read write
IsProbeMode protected (declared in TROTransportChannel)
property IsProbeMode: Boolean read
LoadBalancerLocatorIdx (declared in TROTransportChannel)
property LoadBalancerLocatorIdx: Integer read write
MaxPackageSize
Sets the maximum size for data packages that the channel will transport (default is 10485760, 10 MB).
property MaxPackageSize: Integer read write
OnAfterProbingServer
Fires after the channel is done probing a specific server for availability. You can use this event to check the result of the probing, possibly to update internal data structures or to display server status in the user interface.
property OnAfterProbingServer: TROEndProbeServerEvent read write
OnAfterProbingServers
Fires after the channel is done probing all servers for availability. You can use this event to check the result of the probing, possibly to update internal data structures or to display server status in the user interface.
property OnAfterProbingServers: TROEndProbeServersEvent read write
OnBeforeProbingServer
Fires before the channel starts probing a specific server for availability. You can use this event to:
- check or adjust the server configuration
- to include/exclude the server from being probed by changing the TROServerLocator property.
property OnBeforeProbingServer: TROBeginProbeServerEvent read write
OnBeforeProbingServers
Fires before the channel starts probing all servers for availability. You can use this event:
- to check or adjust the server configurations
- to include/exclude individual server from being probed by changing their TROServerLocator properties.
property OnBeforeProbingServers: TROBeginProbeServersEvent read write
OnLoginNeeded
Fires if an EROSessionNotFound (or the descendant SessionNotFoundException) exception is raised during the execution of a remote request. This usually indicates that the server cannot authenticate the client or that the session has expired. The most common use for this event is to perform a call to a special Login service provided by the server (possibly after prompting the user to enter username and password), and to set the aRetry parameter to true if login was successful.
property OnLoginNeeded: TROExceptionEvent read write
OnProgress
This event fires as the channel is transferring data for a request or response to or from the server, informing of the current progress. It can be used to keep the user interface updated during lengthy transfers,e.g. by showing a progress bar or the remaining transfer volume. Note: the accuracy and frequency of calls to OnProgress depends on the channel type; since channels transport data packets in different sized chunks (or even all-at-once), OnProgress might show a very fine progress for some channels, while jumping from 0 to 100% in one step with others.
property OnProgress: TProgressEvent read write
OnReceiveStream
Fires after a stream with a response message has been received from the server. Use this event handler to inspect and possibly modify the stream, before it continues to be processed by the higher levels of the Remoting SDK framework.
property OnReceiveStream: TStreamDispatch read write
OnSendStream
Fires just as a stream with a request message will be sent to the server. The event handler can inspect and possibly modify the stream, before it continues to be sent off to the server.
property OnSendStream: TStreamDispatch read write
OnServerLocatorAssignment
Fires before changing of a server locator.
property OnServerLocatorAssignment: TServerLocatorAssignment read write
ProbeFrequency
Sets at what intervals, in milliseconds, the channel will probe the servers configured in ServerLocators for availability. The default value is 60,000 (60 seconds). See the ProbeServers property for a more detailed description. Although somewhat misnamed, this property defines the Interval between probes, not the actual probing Frequency. The property name is persisted for backward compatibility.
property ProbeFrequency: Cardinal read write
ProbeServers
Toggles whether the channel will continuously probe the servers configured in ServerLocators for availability. If enabled (true), the channel will ping all servers at a regular interval to determine if they are reachable. If a server fails to respond, it will be disabled for future calls until a later probe can reach it again. The interval between probes can be configured using the ProbeFrequency property. By default, server probing is turned off.
property ProbeServers: Boolean read write
ReconnectDelay protected
The time interval to pass between reconnect attempts, in millisecnds. The default is 500 (0.5 second).
property ReconnectDelay: Integer read write
RequestTimeout
The timeout to complete the remote request on the server. Expressed in milliseconds, the default value is 60000 (60 sec). All requests that last longer than the timeout specified are considered failed.
property RequestTimeout: Integer read write
ServerLocators
Optionally, this collection property can be filled to contain a list of possible servers to be used for fail-over or load balancing purposes. Depending on the settings configured in DispatchOptions, the channel will automatically spread calls over the available servers, or fall back to another server if one fails.
property ServerLocators: TROServerLocatorCollection read write
SessionId protected
The unique identifier of the current session on the server. The same as ClientId.
property SessionId: TGUID read write
StoreActive
Controls whether the Active property value is stored in the dfm file.
property StoreActive: Boolean read write
SynchronizedProbing
Determines whether server probing happens in the context of the main VCL thread (true, default) or in a background worker thread. See the ProbeServers property for a more detailed description.
property SynchronizedProbing: Boolean read write
SynchronizeEvents
According to the superchannel nature every remote request is processed using it's own background thread. This property controls on which thread to execute the event handlers for events connected with each remote request. If the property is set to true than all event handlers are executed on the main application thread, otherwise they are executed on the request's background thread.
WARNING: This property has no effect on OnSendStream and OnReceiveStream events, they are always executed in main thread.
property SynchronizeEvents: Boolean read write
TargetUri (declared in TROTransportChannel)
Target URI
property TargetUri: TROUri read write
TargetUrl
The address of the server.
property TargetUrl: string read write
ThreadSafe protected (declared in TROTransportChannel)
property ThreadSafe: Boolean read write
WaitingRequests protected
Internal storage of remote requests awaiting for response.
property WaitingRequests: TThreadList<TROWaitingRequest> read
WorkerThread protected
Internal background threads management property.
property WorkerThread: TThread read
ChannelMatchingTargetUri (declared in TROTransportChannel)
Creates a client channel instance with type, target host and target port matching the provided target Uri.
F.e. for provided uri supertcp://192.168.1.100:7020/bin this method will return an instance of the Super Tcp channel with target host set to 192.168.1.100 and port set to 7020.
class function ChannelMatchingTargetUri(const aUri: TROUri): TROTransportChannel
Parameters:
- aUri: Server Uri
ChannelMatchingTargetUrl (declared in TROTransportChannel)
class function ChannelMatchingTargetUrl(const aUrl: string): TROTransportChannel
Parameters:
- aUrl:
constructor Create override
Standard component constructor
constructor Create(aOwner: TComponent)
Parameters:
- aOwner: Owner
Assign override (declared in TROTransportChannel)
Copies the contents of another, similar object.
procedure Assign(Source: TPersistent)
Parameters:
- Source: Instance whose properties will be copied
AssignEvents protected override
Copies the events of another, similar object.
procedure AssignEvents(aSource: TROTransportChannel)
Parameters:
- aSource: Instance whose properties will be copied
AssignSpecificProperties protected override
Copies the specific properties of another, similar object.
procedure AssignSpecificProperties(aSource: TROTransportChannel)
Parameters:
- aSource: Instance whose properties will be copied
AsyncException protected virtual (declared in TROTransportChannel)
Notifies about an exception in an asynchronous mode.
procedure AsyncException(aAsyncInterface: IROAsyncInterface; AsyncException: Exception)
Parameters:
- aAsyncInterface: Exception source
- AsyncException: Exception data
BeforeDispatch protected override
Allows an implimentation to do necessary preparatory actions (checking the readiness of the channel, restore session data, etc.).
procedure BeforeDispatch(aMessage: IROMessage)
Parameters:
- aMessage: Message
CallbackEvents protected (declared in TROBaseActiveEventChannel)
Sends event to each registered IROEventReceiver
procedure CallbackEvents(aData: TStream; aThread: TThread)
Parameters:
- aData: Data stream
- aThread: Working thread to process the event
ChangeServerLocator protected override
procedure ChangeServerLocator(var aFaultStartLocatorIdx: Integer; var aRetry: Boolean; const aException: Exception)
Parameters:
- aFaultStartLocatorIdx:
- aRetry:
- aException:
CheckProperties virtual (declared in TROTransportChannel)
Validates channel properties
procedure CheckProperties
CheckStatus protected
Indicates whether an answer is received after an InvokeRequest.
function CheckStatus(const aMessageID: string): Boolean
Parameters:
- aMessageID: Value of the previously called InvokeRequest result
CreateWorkerThread protected virtual abstract
function CreateWorkerThread: TThread
DecryptStream (TStream, TStream) protected overload (declared in TROBaseConnection)
Decrypt stream
procedure DecryptStream(const Source: TStream; const Dest: TStream)
Parameters:
- Source: Source
- Dest: Destination
DecryptStream (TStream) protected overload (declared in TROBaseConnection)
Decrypt stream
procedure DecryptStream(const Stream: TStream)
Parameters:
- Stream: Stream
Dispatch (IROMessage) protected reintroduce overload (declared in TROTransportChannel)
Sends a request message through the Self
channel for processing and gets back an aMessage
. CodeGen uses this method when generating a proxy from RODL Files.
procedure Dispatch(aMessage: IROMessage)
Parameters:
- aMessage: (In/out) message data
DoAfterProbingServerEvent protected override
Fires OnAfterProbingServer event
procedure DoAfterProbingServerEvent(const aServerLocator: TROServerLocator; const aFailed: Boolean)
Parameters:
- aServerLocator: Server locator
- aFailed:
DoAfterProbingServersEvent protected override
Fires OnAfterProbingServer event
procedure DoAfterProbingServersEvent(const aProbedCount: Integer; const aEnabledCount: Integer; const aDisabledCount: Integer)
Parameters:
- aProbedCount:
- aEnabledCount:
- aDisabledCount:
DoBeforeDecryptEvent protected virtual (declared in TROBaseConnection) obsolete
procedure DoBeforeDecryptEvent(aEncryptedStream: TStream)
Parameters:
- aEncryptedStream: Stream
DoBeforeProbingServerEvent protected override
Fires OnBeforeProbingServer event
procedure DoBeforeProbingServerEvent(const aServerLocator: TROServerLocator)
Parameters:
- aServerLocator: Server locator
DoBeforeProbingServersEvent protected override
Fires OnBeforeProbingServers event
procedure DoBeforeProbingServersEvent
DoNeedSSL protected virtual (declared in TROTransportChannel)
Detects SSL state
function DoNeedSSL: Boolean
DoProcessError protected
function DoProcessError(const aId: Integer; const aErrorNo: Integer): Boolean
Parameters:
- aId:
- aErrorNo:
DoReceiveStreamEvent protected override
Fires OnSendStream event
procedure DoReceiveStreamEvent(const Dest: TStream)
Parameters:
- Dest: Stream
DoReconnect protected
procedure DoReconnect(var aRestartLoop: Boolean)
Parameters:
- aRestartLoop:
DoSendStreamEvent protected override
Fires OnSendStream event
procedure DoSendStreamEvent(const Source: TStream)
Parameters:
- Source: Stream
DoServerLocatorAssignmentEvent protected override
Fires OnServerLocatorAssignment event
procedure DoServerLocatorAssignmentEvent(const aLocator: TROServerLocator; const aException: Exception)
Parameters:
- aLocator:
- aException:
EncryptStream (TStream, TStream) protected overload (declared in TROBaseConnection)
Encrypt stream
procedure EncryptStream(const Source: TStream; const Dest: TStream)
Parameters:
- Source: Source
- Dest: Destination
EncryptStream (TStream) protected overload (declared in TROBaseConnection)
Encrypt stream
procedure EncryptStream(const Stream: TStream)
Parameters:
- Stream: Stream
FindWaitingRequest protected
function FindWaitingRequest(aList: TList<TROWaitingRequest>; aId: Integer): TROWaitingRequest
Parameters:
- aList:
- aId:
GetBusy protected virtual (declared in TROTransportChannel)
Returns current channel state
function GetBusy: Boolean
GetChannelFromPool protected virtual (declared in TROTransportChannel)
function GetChannelFromPool: TROTransportChannel
GetStrippedTargetUrl protected virtual
function GetStrippedTargetUrl: string
GetTransportObject protected virtual (declared in TROTransportChannel)
Returns itself.
function GetTransportObject: TObject
HasData protected
This method is called when incoming data is present.
procedure HasData(aId: Integer; aData: TStream)
Parameters:
- aId:
- aData:
InDestroyingState protected
Returns current state
function InDestroyingState: Boolean
InitialConnect protected
function InitialConnect: Boolean
InitServerLocator protected override
Sets CurrentLocator
function InitServerLocator: Integer
InitWorkerThread protected
procedure InitWorkerThread
InvokeRequest protected
Indicates whether an answer is received after an InvokeRequest.
function InvokeRequest(aRequest: TStream; aGetResponse: Boolean): string
Parameters:
- aRequest: Id of a waiting response
- aGetResponse: Response data
IsEncryptionUsed protected (declared in TROBaseConnection)
Checks if encryption was used
function IsEncryptionUsed: Boolean
IsStreamEncrypted protected (declared in TROBaseConnection)
Checks state of stream
function IsStreamEncrypted(Source: TStream): Boolean
Parameters:
- Source: Stream
LaunchAsyncTask protected (declared in TROTransportChannel)
procedure LaunchAsyncTask(aRequest: IROAsyncRequest)
Parameters:
- aRequest:
LoadSSL protected virtual (declared in TROTransportChannel)
Loads SSL library if SSL protocol is used
procedure LoadSSL
Notification protected override
Forwards notification messages to all owned components.
procedure Notification(AComponent: TComponent; Operation: TOperation)
Parameters:
- AComponent: component
- Operation: operation
Probe protected (declared in TROTransportChannel)
Checks the accessibility of servers from the ServerLocators. This method is intended to provide fail-over and load balancing support in the Remoting SDK Architecture.
function Probe(aServerLocator: TROServerLocator): Boolean
Parameters:
- aServerLocator: Server locator
ProbeAll protected (declared in TROTransportChannel)
Checks the availability of all known servers.
procedure ProbeAll
ProcessEvent protected
procedure ProcessEvent(aData: TStream)
Parameters:
- aData:
RegisterEventReceiver protected virtual (declared in TROBaseActiveEventChannel)
Registers a new event receiver object aReceiver in the specified channel. This procedure is needed to further use the aReceiver as receiver for callback events.
procedure RegisterEventReceiver(aReceiver: IROEventReceiver)
Parameters:
- aReceiver: the event receiver that should be registered.
ResetProbingClone protected override
Resets channel that is used for probing
procedure ResetProbingClone(aProbe: TROTransportChannel)
Parameters:
- aProbe: Probing clone
RetrieveMetadata protected virtual (declared in TROTransportChannel)
Returns server-side RODL.
procedure RetrieveMetadata(out Dest: TStream)
Parameters:
- Dest: Stream
RetrieveResponse protected
Indicates whether an answer is received after an InvokeRequest.
procedure RetrieveResponse(const aMessageID: string; aResponse: TStream)
Parameters:
- aMessageID: Id of a waiting response
- aResponse: Response data
RetrieveRODL protected (declared in TROTransportChannel)
This method is used for to obtaining the RODL library from the server without havin to rely on a channel-specific mechanism (such as a HTTP request to http://servername:port/rodl).
procedure RetrieveRODL(out RODLLibrary: TRODLLibrary)
Parameters:
- RODLLibrary: Result
ReturnChannelToPool protected virtual (declared in TROTransportChannel)
procedure ReturnChannelToPool(aChannel: TROTransportChannel)
Parameters:
- aChannel:
ROActiveAsyncTransportChannel_InvokeRequest (TStream, Boolean, TROEvent): string protected overload virtual abstract
function ROActiveAsyncTransportChannel_InvokeRequest(aRequest: TStream; aGetResponse: Boolean; aEvent: TROEvent): string
Parameters:
- aRequest:
- aGetResponse:
- aEvent:
ROFreeNotification (declared in TROComponent)
Forwards notification messages to all owned components.
procedure ROFreeNotification(aComponent: TComponent)
Parameters:
- aComponent: component
RORemoveFreeNotification (declared in TROComponent)
Forwards notification messages to all owned components.
procedure RORemoveFreeNotification(aComponent: TComponent)
Parameters:
- aComponent: component
SendRemoveNotification protected (declared in TROComponent)
Forwards notification messages to all owned components.
procedure SendRemoveNotification(aComponent: TComponent)
Parameters:
- aComponent: component
SetAsyncBusy protected override
procedure SetAsyncBusy(const Value: Boolean)
Parameters:
- Value:
SetConnectedState protected
procedure SetConnectedState
SetInactive protected virtual
procedure SetInactive
SetServerLocator protected (declared in TROTransportChannel)
Retrieves the location details of a server from aServerLocator
.
procedure SetServerLocator(aServerLocator: TROServerLocator; anException: Exception)
Parameters:
- aServerLocator: Configuration data of the server
- anException: Exception
SuperChannel_RaiseError protected virtual abstract
procedure SuperChannel_RaiseError(aCode: Integer)
Parameters:
- aCode:
TerminateWorkerThread protected
procedure TerminateWorkerThread
TriggerProgress protected override
Fires OnProgress event
procedure TriggerProgress(aType: TProgressType; aDirection: TProgressDirection; aTransfered: Integer; aTotal: Integer)
Parameters:
- aType: progress type
- aDirection: direction
- aTransfered: transfered bytes
- aTotal: total bytes
UnregisterEventReceiver protected virtual (declared in TROBaseActiveEventChannel)
Unregisters the specified IROEventReceiver aReceiver in the specified channel.
procedure UnregisterEventReceiver(aReceiver: IROEventReceiver)
Parameters:
- aReceiver: The event receiver that should be unregistered.
UnregisterEventReceivers protected (declared in TROBaseActiveEventChannel)
Unregisters the all event receivers in the specified channel.
procedure UnregisterEventReceivers
WaitForActive
procedure WaitForActive(const aTimeout: Integer)
Parameters:
- aTimeout:
ConnectEvent
property ConnectEvent: TROEvent read
OnAfterEncrypt (declared in TROBaseConnection)
Fired after stream was encrypted
property OnAfterEncrypt: TROBaseConnectionOperation read write
delegate: procedure OnAfterEncrypt(Sender: TROBaseConnection; aEncryptedStream: TStream)
OnAsyncException (declared in TROTransportChannel)
Fires when exception is raised in asynchronous mode
property OnAsyncException: TROAsyncExceptionEvent read write
delegate: procedure OnAsyncException(Sender: TROTransportChannel; Async: IROAsyncInterface; anException: Exception)
OnBeforeDecrypt (declared in TROBaseConnection)
Fired before stream will be decrypted
property OnBeforeDecrypt: TROBaseConnectionOperation read write
delegate: procedure OnBeforeDecrypt(Sender: TROBaseConnection; aEncryptedStream: TStream)
OnConnected
Fires when channel is connected to server
property OnConnected: TNotifyEvent read write
OnDisconnected
Fires when the active connection to the server has been dropped or lost.
property OnDisconnected: TNotifyEvent read write
OnException (declared in TROTransportChannel)
Fires if an exception is raised during the execution of a remote request.
This could be an exception returned from the server, a communication problem or an error within the client.
Depending on the type of error, your event handler can try to rectify the problem, and set aRetry to true to have the channel try and perform the request again. For example, an application could show a dialog asking the user to confirm if his internet connection is available, with Cancel and Retry buttons.
If aRetry is set to true and the call succeeds at the second attempt, the call will return to the original code that initiated the request, as if the exception never happened.
property OnException: TROExceptionEvent read write
delegate: procedure OnException(Sender: TROTransportChannel; anException: Exception; var aRetry: Boolean)
ReconnectEvent
property ReconnectEvent: TROEvent read